Cerebral hemodynamics and oxygen metabolism in sickle cell disease An MRI-based approach

In patients with sickle cell disease (SCD), SCD-related complications can induce cerebral abnormalities like silent cerebral infarcts (SCIs). Understanding the pathophysiological mechanisms behind these lesions is therefore important. Parameters related to cerebral hemodynamics and oxygen metabolism, quantifiable through noninvasive MRI techniques, offer insights into SCD's impact on brain health.
In this thesis, brain health is assessed by analyzing cerebral hemodynamics and oxygen metabolism across various anemic populations and healthy controls. In Chapter 2, using the arterial spin labeling technique, a novel quantitative parameter for functional shunting is introduced, which might be crucial for understanding impaired oxygen metabolism in severe SCD patients. Chapters 3 and 4 examine cerebral perfusion, oxygenation and the presence and volume of SCIs in patients with both mild and severe forms of SCD, as well as in thalassemia patients and healthy controls. Results indicate that, despite the presence of SCIs, hemodynamics and oxygen metabolism differ among these groups. Chapter 5 explores various neurocognitive domains in patients with SCD and thalassemia, as well as in healthy controls. The associations of these domains with SCIs and the parameters of hemodynamics and oxygen metabolism are also investigated. Lastly, Chapter 6 studies the effect of hematopoietic stem cell transplantation on the parameters of hemodynamics and oxygen metabolism. In conclusion, these studies suggest that cerebral hemodynamics and oxygen metabolism can be noninvasively assessed in different anemic groups using functional MRI techniques. Such techniques may assist hematologists in determining the most effective treatments for their patients.